1. Field of the Invention
This application relates to a dual-stage hybrid inflator which is filled with pressurized gas and different dosage of propellant and is initiated by igniters disposed thereon, so as in order to generate various degrees of gas depended on various degrees of collision.
2. Description of the Related Art
An airbag system is known as standard equipment for automobiles, and an inflator equipped is capable of inflating the airbag quickly to provide a buffering space, which is provided for protecting passengers or drivers during occurrence of a car accident.
There are three main methods of inflating the automobile airbags as described below. In first method, a gas-compressed air inflator uses a pressurized gas stored in an air cylinder as a gas source for inflating the airbag and the pressurized gas is released rapidly when the gas is needed. However, such inflator has the drawbacks of requiring a relatively larger gas storage and pressure, and thus causing greater volume, thickness and weight of the air cylinder and incurring a higher cost and more limitation on its application. In second method, a pyrotechnic inflator fills propellant therein, and the igniter will ignite the propellant to produce gas and fill up an airbag. However, such inflator has the drawback of producing a high temperature gas which may damage the airbag easily or burn or injure the passengers, and the solid residue and toxic gases remained after the combustion jeopardize our health and environment. In third method, a hybrid inflator fills with few propellant and pressurized gas, so as to achieve the effects of the aforementioned two types of inflators, preventing accidents caused by the too-high temperature, and providing an easier installation due to the smaller and lighter air cylinder. However, this kind of hybrid inflator has more complicated structure and design, and specific manufacturing process is needed such that application thereof can be made.
However, such hybrid inflator is limited by the amount of propellants and the sealing technology of the pressurized gas cylinder. The conventional dual-stage inflator can be combined with various sensors to release adequate amount of gas, and the airbag with a better protection effect can be provided. The hybrid inflator, nonetheless, the filled propellant is covered by high pressurized gas, which has higher burning quality. If a dual-stage one is provided, the second-stage propellant may be ignited accidently in the process of the first-stage operation. As a result, many factors must be taken into consideration to produce a dual-stage inflator as it is relatively of more difficult manufacturing technique, and costs much higher, and thus lacks for practicability.
Based on the foregoing reasons, the inventor of the present invention designs a dual-stage hybrid inflator, in hopes of overcoming the drawbacks of the prior art and improving the industrial application.